U.S. patent application number 11/252210 was filed with the patent office on 2006-07-20 for fixture for slider lapping, lapping device and lapping method.
This patent application is currently assigned to SAE Magnetics (H.K) Ltd.. Invention is credited to Ryuji Fujii, XiaoMing Hong, Koji Hosaka, GuoWei Li, XiangBin Xiao.
Application Number | 20060160473 11/252210 |
Document ID | / |
Family ID | 36684575 |
Filed Date | 2006-07-20 |
United States Patent
Application |
20060160473 |
Kind Code |
A1 |
Fujii; Ryuji ; et
al. |
July 20, 2006 |
Fixture for slider lapping, lapping device and lapping method
Abstract
A fixture for slider lapping includes a holding portion for
holding the object with its surface to be lapped toward the lapping
surface of the lapping device; a main body for mounting the lapping
fixture to the lapping device; a plurality of load-applied portions
which are arranged along said longitudinal direction and
independent from said main body, said load-applied portions
receiving a load which presses the surface to be lapped to the
lapping surface tightly from at least the lapping device; a
plurality of connection members connecting said holding portion and
said main body along said longitudinal direction at intervals; and
a plurality of wrist portions connecting said connection members
and said holding portion; wherein at least one wrist portion is
disposed between said adjacent connection members; at least one
wrist portion is disposed at each outer side of the connection
members which are located at both ends of the longitudinal
direction. Also disclosed is a lapping device and method using the
fixture.
Inventors: |
Fujii; Ryuji; (Hong Kong,
CN) ; Hosaka; Koji; (Hong Kong, CN) ; Li;
GuoWei; (Guangdong, CN) ; Hong; XiaoMing;
(Dongguan, CN) ; Xiao; XiangBin; (Dongguan,
CN) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Assignee: |
SAE Magnetics (H.K) Ltd.
Hong Kong
CN
|
Family ID: |
36684575 |
Appl. No.: |
11/252210 |
Filed: |
October 18, 2005 |
Current U.S.
Class: |
451/41 ;
G9B/5.094 |
Current CPC
Class: |
G11B 5/3103 20130101;
G11B 5/3173 20130101; B24B 37/048 20130101; G11B 5/3116 20130101;
G11B 5/3163 20130101; B24B 37/30 20130101; G11B 5/3169 20130101;
G11B 5/3967 20130101 |
Class at
Publication: |
451/041 |
International
Class: |
B24B 7/30 20060101
B24B007/30; B24B 1/00 20060101 B24B001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 18, 2004 |
CN |
200410085493.X |
Claims
1. A lapping fixture, which is mounted to a lapping device for
holding and lapping an object to be lapped and has a longitudinal
direction, comprising: a holding portion for holding the object
with its surface to be lapped toward the lapping surface of the
lapping device; a main body for mounting the lapping fixture to the
lapping device; a plurality of load-applied portions which are
arranged along said longitudinal direction and independent from
said main body, said load-applied portions receiving a load which
presses the surface to be lapped to the lapping surface tightly
from at least the lapping device; a plurality of connection members
connecting said holding portion and said main body along said
longitudinal direction at intervals; and a plurality of wrist
portions connecting said connection members and said holding
portion; wherein at least one wrist portion is disposed between
said adjacent connection members; at least one wrist portion is
disposed at each outer side of the connection members which are
located at both ends of the longitudinal direction.
2. The lapping fixture as claimed in claim 1, wherein said two
wrist portions disposed at both outmost ends of said longitudinal
direction are located at a position which is adjacent to a position
for fixing two end portions of said object to be lapped in the
longitudinal direction.
3. The lapping fixture as claimed in claim 1, wherein the
load-applied portions receive at least load for sliding said
surface to be lapped on the lapping surface along said longitudinal
direction, or load for rotating said surface to be lapped around an
axis which is perpendicular to both said pressing direction and
longitudinal direction.
4. The lapping fixture as claimed in claims 1, wherein said two
connection members are disposed symmetrically along the
longitudinal direction.
5. The lapping fixture as claimed in claims 1, wherein the main
body is made of a kind of material containing SiC.
6. A lapping device, comprising: a lapping fixture of claim 1; a
load applied mechanism to transfer load in pressing direction to
said load-applied portions; and a lapping surface.
7. A method for lapping an object having a longitudinal direction,
comprising the steps of: pressing a holding portion, by which the
object to be lapped with a longitudinal direction is held, toward
the lapping surface at first positions separated at intervals along
a longitudinal direction of the holding portion, and making the
surface to be lapped of the object contact with the lapping
surface; moving said surface to be lapped relative to the lapping
surface; and providing the holding portion with a load in second
regions which comprise regions between said adjacent first
positions and regions beyond said first positions, and lapping said
surface to be lapped of said object, said load being perpendicular
to the lapping surface and pressing the surface to be lapped toward
the lapping surface.
8. The method for lapping as claimed in claim 7, wherein said two
second positions disposed at outmost sides of the longitudinal
direction are located at a position adjacent to both end portions
of said object to be lapped.
9. The method for lapping as claimed in claim 7, further
comprising: providing the holding portion at said second positions
with load for sliding said surface to be lapped on the lapping
surface along said longitudinal direction, or load for rotating
said surface to be lapped around an axis which is perpendicular to
both said pressing direction and longitudinal direction.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a method for manufacturing
sliders incorporating thin film magnetic heads, and more
particularly to a slider lapping fixture, lapping device and
lapping method for improving the flatness in longitudinal direction
of a row bar which is constructed by an array of sliders.
BACKGROUND OF THE INVENTION
[0002] As a recording media with high-speed, sufficient capacity,
strong reliability and low cost, disk drives are widely used for
digital information recording. After the technology development for
many years, the recording density of a disk drive has been
developed to exceed 100 GB per square inch. The disk drive includes
a slider incorporating a thin film head for recording and
reproducing data information stored in a recording media. The
slider has a surface facing to the recording media which is
referred as air bearing surface (ABS).
[0003] For an MR element (magneto-resistive element, MR element)
which reads information from the recording media, it is important
to maintain height of the MR element (the height measured
vertically from the ABS to the MR element) to its design value for
ensuring reading performance of the MR element.
[0004] Because the height of MR element is obtained by lapping the
ABS firstly, then removing the rest of the MR element, in process
of depositing an MR element which has an original height larger
than it's design value on a wafer, it is important to maintain the
precision of lapping clearance of the ABS and thus maintaining the
precision of the MR element height.
[0005] Further, it is important for an inductive magnetic element
which writes information to the recording medium to make the throat
height (the height of two opposing poles used for writing operation
measured vertically from the ABS) as its design value. It is also
important to maintain the precision of lapping clearance of the
ABS, since the throat height is also attained by lapping the
ABS.
[0006] However, because the lapping surface is disposed in a
vertical direction with respect to a wafer surface which is formed
two-dimensionally by pluralities of sliders, the wafer need to be
sliced in advance in lapping processing so as to expose the lapping
surface. Therefore, it is necessary to cut the wafer along a
direction at which the lapping surface is disposed into a plurality
of row bars formed by an array of sliders, and the lapping surface
is lapped together with the row bar (further dicing the row bar
into individual sliders and lapping in slider level is low
efficient and therefore is unpractical). The row bar is supported
by a predetermined fixture, then pressed onto a revolving lapping
table and lapped, as disclosed in U.S. Pat. No. 5,607,340 and U.S.
Pat. No. 5,620,356.
[0007] In lapping process of the row bar, it is very important to
maintain not only the clearance precision of each part which form
an entire slider, but also that of the whole row bar, i.e., it is
critical to grind evenly the whole row bar for ensuring it's
flatness.
[0008] However, in row bar lapping process using conventional
technology, as the press force applied to the row bar is
distributed unevenly along the longitudinal direction of the row
bar, thus lapping clearance deviation is produced along
longitudinal direction. Accordingly, problems arise, such as MR
element height or throat height of a slider thus formed can not get
its designed value and product yield of non-defective sliders
decreases. One reason lies in: in fact the contour of the lapping
surface of row bar should be approximately a curve of at least
sixth order with respect to longitudinal direction of the row bar,
while conventional row bar supporting method can simulate only
curve of fourth order at most, and thus will result in low product
yield, as disclosed in JP patent publication NO. 2000-11315.
Therefore, a method for improving contour control freedom of the
lapping surface is disclosed as follow: deforming freedom exists on
a load applying member used for applying load to a row bar not only
at direction toward which the row bar is pressed, but also along
longitudinal direction and rotation direction of the row bar for
improving control freedom, as disclosed in JP patent application
NO. 3,537,726.
[0009] FIG. 8 shows a side view of a conventional fixture used in a
lapping process. The lapping fixture 150 comprises a main body 151,
a holding body 152 used for retaining the row bar (not shown), and
a plurality of connection members 153a-153d (four connection
members are shown in the figure) which connect the main body 151
and holding body 152. The row bar is secured to a row bar securing
portion 158 formed at the front end of the holding body 152. In
addition, the lapping fixture 150 further comprises a plurality of
load-applied members 154a-154g for pressing the holding body to a
revolving lapping table (not shown). The load-applied members
154a-154g are kept tight contact with the revolving lapping table
by a plurality of load applying components which are inserted
through holes of the load-applied members 154a-154g respectively,
and then the row bar mounted on the row bar securing portion 158 is
lapped. The lapping fixture 150 further comprises attaching holes
156, and matching portions 157a and 157b used for supporting the
lapping fixture 150. A fixing pin (not shown) is inserted through
the hole 156 and the lapping fixture 150 is mounted to a lapping
device. Each of the matching portions 157a and 157b has a guide pin
(not shown) inserted therethrough and the excessive displacement of
the main body 151 is prevented from happening by mutual engagement
formed between the matching portions 157a, 157b and guide pins.
SUMMARY OF THE INVENTION
[0010] To overcome the above shortcomings of the prior art, the
present invention provides a lapping fixture which is mounted to a
lapping device so as to lap an object which is to be lapped and
which has a longitudinal direction, and the lapping fixture of the
invention is used for retaining the object to be lapped.
[0011] The lapping fixture of the invention comprises a holding
portion for holding the object with its surface to be lapped toward
the lapping surface of the lapping device; a main body for mounting
the lapping fixture to the lapping device; a plurality of
load-applied portions which are arranged along said longitudinal
direction and independent from said main body, said load-applied
portions receiving a load which presses the surface to be lapped to
the lapping surface tightly from at least the lapping device; a
plurality of connection members connecting said holding portion and
said main body along said longitudinal direction at intervals; a
plurality of wrist portions connecting said connection members to
said holding portion. At least one wrist portion is disposed
between said adjacent connection members, and at least one wrist
portion is disposed at each outer side of the connection members
which are located at both ends of the longitudinal direction.
[0012] For the lapping fixture thus constructed, the load coming
from the load-applied portions is transferred to the regions
between connection members and regions beyond the outer sides of
the connection members which are disposed at both ends. Therefore,
enough pressing load can be applied to regions which are beyond the
outer sides of the end connection members and where pressing load
is insufficient, i.e., the pressing load can be transferred to
regions adjacent the both end sides of the row bar. In addition,
pressing load may be applied to at least one portion in regions
between the connection members, thus, phenomena of rolling up of
other region due to pressing load applied to other region can be
prevented from happening.
[0013] Preferably, said two wrist portions disposed at both outmost
ends of said longitudinal direction are adjacent two end portions
of the longitudinal direction, said object to be lapped being
attached along the longitudinal direction. Additionally, the
load-applied portions receive at least load for sliding said
surface to be lapped on the lapping surface along said longitudinal
direction, or load for rotating said surface to be lapped around an
axis which is perpendicular to both said pressing direction and
longitudinal direction. Furthermore, two said connection members
are disposed symmetrically along the longitudinal direction, and
the main body is made of a kind of material containing SiC.
[0014] Moreover, the lapping device of the invention comprises a
lapping fixture as described above, a load-applied mechanism to
transfer load in pressing direction to said load-applied portions,
and a lapping surface.
[0015] The lapping method of the invention is used for lapping an
object to be lapped having a longitudinal direction. The lapping
method comprises the steps of: pressing the holding portion, by
which the object to be lapped with a longitudinal direction is
held, toward the lapping surface at first positions separated at
intervals along the longitudinal direction of the holding portion,
and making the surface to be lapped of the object contact with the
lapping surface; moving said surface to be lapped relative to the
lapping surface; and providing the holding portion with a load in
second regions which comprise regions between said adjacent first
positions and regions beyond said first positions, and lapping said
surface to be lapped of said object, said load being perpendicular
to the lapping surface and pressing the surface to be lapped toward
the lapping surface. Preferably, said two second positions disposed
at outmost sides of the length are located adjacent both end
portions of said object to be lapped.
[0016] In addition, the lapping method may also includes a step of:
providing the holding portion at said second positions with load
for sliding said surface to be lapped on the lapping surface along
said longitudinal direction, or load for rotating said surface to
be lapped around an axis which is perpendicular to both said
pressing direction and longitudinal direction.
[0017] As illustrated above, the pressing load may be applied
suitably to all regions of the row bar by the lapping fixture, the
lapping device and lapping method of the invention. As a result,
the row bar constructed with a plurality of sliders may be lapped
evenly along its longitudinal direction without decreasing
production efficiency or complicating the whole device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings facilitate understanding of the
various embodiments of this invention. In such drawings:
[0019] FIG. 1 schematically shows a perspective view of a lapping
device of the invention;
[0020] FIG. 2 is a side view of a fixture holding portion and a
load adjusting portion of the lapping device shown in FIG. 1;
[0021] FIG. 3 is a perspective view of the load adjusting portion
shown in FIG. 2;
[0022] FIG. 4 is a side cross-sectional view of the fixture holding
portion and the load adjusting portion with a lapping fixture
mounted thereon;
[0023] FIG. 5 is an exploded, perspective view of the load
adjusting portion;
[0024] FIG. 6A is a top plan view of the lapping fixture of the
invention;
[0025] FIG. 6B is a side view of the lapping fixture of the
invention;
[0026] FIG. 6C is a side view of the lapping fixture of the
invention;
[0027] FIG. 6D is a bottom plan view of the lapping fixture of the
invention;
[0028] FIG. 7 is an illustrative view showing advantages produced
by the lapping fixture of the invention;
[0029] FIG. 8 is a top plan view of a conventional lapping fixture;
and
[0030] FIG. 9 is an illustrative view showing drawbacks of the
conventional lapping fixture.
DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS
[0031] Various embodiments of the invention will now be described
in detail in conjunction with the drawings
[0032] FIG. 1 schematically shows a perspective view of a lapping
device according to an embodiment of the invention. The lapping
device 1 is utilized for lapping a bar-shaped member for forming
slider, i.e., a row bar, which is constructed by an array of
sliders. The lapping device 1 comprises a working table 10, a
revolving lapping table 11 supported on the working table 10, a
support post 12 disposed at one side of the revolving lapping table
12, an arm portion 13 extending from the support post 12 and over
the revolving lapping table 11, and a support member 20 carried by
the arm portion 13. The revolving lapping table 12 has a lapping
surface 11a thereon for lapping the row bar.
[0033] The support member 20 includes a support portion body 27
connected to the arm portion 13, a carrying base 22 located at the
front end of the support portion body 27, a fixture holding portion
23 disposed at the front side of the carrying base 22 and a
plurality of load adjusting portions 24a-24g (only 24a is shown in
the figure) formed independently from each other. All the
components of the support member 20 are covered by a cover 21. The
carrying base 22 is connected via the arm portion 13 to an actuator
(not shown ) disposed on the support portion body 27, and the
carrying base 22 can move up and down when being driven by the
actuator. A lapping fixture 50 used for lapping a row bar is held
by the fixture holing portion 23.
[0034] FIG. 2 is a side view of the fixture holding portion and
load adjusting portions taken along line 2-2 of FIG. 1. FIG. 3 is a
perspective view of the load adjusting portions 24a, 24d and 24g
shown in FIG. 2. FIG. 4 is a side cross-sectional view of the
lapping fixture taken along lines 4-4 of FIGS. 2, 3, wherein the
fixture holding portion and the load adjusting portion are both
fastened. FIG. 5 is an exploded, perspective view of a load
adjusting portion (only one is shown).
[0035] As illustrated in FIGS. 3-4, the fixture holding portion 23
includes a holding portion body 31, a fixture securing pin 32 and a
pair of guiding pins 33a, 33b. The fixture securing pin 32 extends
forwardly from the middle position of the lower front end of the
holding portion body 31. The guiding pins 33a, 33b extend forwardly
from side positions of the lower front end of the holding portion
body 31 respectively. The holding portion body 31 is connected to a
rotary spindle 44 through a bearing 45 located thereon. In
addition, the fixture holding portion 23 is connected to two
actuators which are disposed on a top surface of the fixture
holding portion 23 and which independently apply pressing force
downwardly to the holding portion body 31 at both sides thereof
(see the hollow arrow shown in FIG. 3 and hollow arrow arranged in
left side of FIG. 4. In addition, the actuators are not shown in
the figures). Accordingly, the holding portion body 31 is pressed
downwardly, and rotates about the rotary spindle 44 by adjusting
the forces applied by the actuators. Furthermore, with the motion
of the holding portion body 31, the guiding pins 33a and 33b are
also pressed downwardly and rotate, thus resulting in downward
displacement different from each other. Moreover, the inclination
of the MR element height may be corrected by rotating the holding
portion body 31. Therefore, the incline angle may be very small and
even limited to .+-.5 degree if a stopper (not shown) is used.
[0036] The fixture securing pin 32 has an inner screw thread formed
at front end thereof, and the lapping fixture 50 is held among a
screw bolt 40, a washer 49 and the fixture securing pin 32 and
fixed thereby. Each of guiding pins 33a, 33b has a circle-shaped
cross-section, and in the front portion of the fixture securing pin
32, the portion thereof is more adjacent to the distal end thereof,
the diameter thereof is smaller.
[0037] Now describing the load adjusting portions 24a-24g. As
illustrated in FIG. 2, the load adjusting portion comprises seven
load adjusting portions 24a-24g which are arranged at front end of
the holding portion body 31 in parallel. All the load adjusting
portions 24a-24g have the same structure and can adjust the load
applied to the row bar independently from each other. In addition,
the level of the load adjusting portions 24a, 24g are higher
slightly than that of the rest load adjusting portions. A through
hole is defined in the load adjusting portion 24d for receiving the
fixture securing pin 32.
[0038] Now taking the load adjusting portion 24d as an example. The
load adjusting portion 24d has a load transfer rod 25d which can
move up and down when driven by an actuator (not shown) disposed on
the carrying base 22. As shown in FIGS. 4-5, the load transfer rod
25d is supported by a support member 43d and can move up and down
and rotate. A cuboid-shaped load applying block 35d is mounted on
the bottom end of the load transfer rod 25d. A bearing member 37d
is disposed on the bottom end of the load applying block 35d, and a
load applying pin 36d can extend through the bearing member 37d and
rotate freely in the bearing member 37d.
[0039] The load adjusting portion 24d is also supported by the
bearing member 37d of the load applying block 35d, and a load
applying pin 36d which projects from the front end of the load
applying block 35d is disposed on the front end of the load
adjusting portion 24d. A cuboid-shaped head portion is formed at
the front end of the load applying pin 36d.
[0040] In addition, as a characterized structure of the load
applying block 35d, a hole 38 is defined in a position
corresponding to the fixture securing pin 32 for receiving the
fixture securing pin 32. The inner diameter of the hole 38 is
larger slightly than the outer diameter of the fixture securing pin
32 such that the load applying block 35d can move freely in
vertical and horizontal directions a predefined distance.
[0041] Then, referring to FIGS. 6A-6D, structure of a lapping
fixture according to one embodiment is illustrated. FIG. 6a shows a
top plan view of the lapping fixture of the embodiment; FIG. 6b
shows a side view of the lapping fixture; FIG. 6c shows a side view
of the lapping fixture; and FIG. 6d shows a bottom plan view
thereof. In following description, the longitudinal direction of
the lapping fixture is defined as x direction; the direction
perpendicular to x direction is defined as y direction; and the
rotation direction around an axis which is perpendicular to both of
x direction and y direction is defined as e direction.
[0042] As illustrated in FIGS. 6A-6D, the lapping fixture 50 of the
embodiment includes a main body 51 mounted on the lapping device 1;
a holding portion 52 which holds a product to be processed, that
is, a row bar 70 along it's longitudinal direction and which is
parallel with the row bar 70; two connection members 53a and 53b
for connecting the holding portion 52 and the main body 51
together; seven load-applied portions 54a-54g connected to the
holding portion 52 and which applies load to the holding portion 52
thus resulting in deformation thereof; and a plurality of wrist
portions 55a-55g which connect the holding portion 52 and
load-applied portions 54a-54g respectively. The two connection
members 53a and 53b are disposed symmetrically at both sides along
longitudinal direction of the lapping fixture 50. In addition,
there exist three wrist portions in middle regions between the
connection portions 53a and 53b, and two wrist portions in outer
regions beyond the two connection portions 53a and 53b along their
longitudinal direction. At least one wrist portion may be formed at
middle regions between the two connection portions and outer
regions beyond the two connection portions, and quantity of the
wrist portions may be altered based on condition such as length of
the product to be lapped and lapping precision. Although the
lapping fixture 50 of the embodiment is made of SiC, other material
such as ceramic, stainless steel, ZrO.sub.2, or Al.sub.2O.sub.3 may
also be used in manufacturing process.
[0043] An attaching hole 56 is formed at middle region of the main
body 51 along its longitudinal direction such that a screw bolt 40
can pass through it. The main body 51 is fixed to the fixture
securing pin 32 of the lapping device 1 by the screw bolt 40 and is
kept stationary with respect to the fixture securing pin 32. The
main body 51 is suspended in one point form at its attaching hole
56 by the lapping device 1. Furthermore, corresponding with the
guiding pins 33a and 33b, matching portions 57a and 57b are formed
on the main body 51 and engage with the guiding pins 33a and 33b,
so as to align the fixture securing pin 32 with the attaching hole
56. The reason of suspending the lapping device 50 in one point
form at the attaching hole 56 lies in: if the lapping fixture is
secured at several positions, the lapping device will deform when
several flexures or crinkles exist in the mounting contact surface
or particle exists between the mounting contact surface and the
lapping device. If the lapping fixture is mounted onto the lapping
device in a deformation state, the original air bear surface (ABS)
and the lapping surface will not be parallel with each other,
instead, there will exist an angle or flexure, and the lapping
process is performed under influence of the angle or flexure,
accordingly, the flatness of the row bar will degrade. On the
contrary, if the lapping fixture 50 is supported in one point form,
the mounting contact surface of the lapping fixture 50 will be
limited to a small area located at front end of the fixture
securing pin 32. Consequently, the deformation of the lapping
fixture 50 can be confined greatly even if the screw bolt 40 is in
its most tight position. Therefore, the ABS flatness of the row bar
70 after it is dismantled from the lapping device 1 is maintained
almost the same as that before the row bar 70 is dismantled from
the lapping device 1. Accordingly, the lapping precision is
maintained constant as well.
[0044] Each matching portions 57a and 57b disposed at both sides of
the main body 51 have an opening facing the inner area of the main
body 51 along its longitudinal direction. In lapping process, the
main body 51 may rotate about the attaching hole 56, since the main
body 51 is supported by one point. Thus the matching portions 57a
and 57b are arranged to prevent this rotation from occurring. The
cross-section of the matching portions 57a and 57b takes form of
rectangle with rounded corners. In longitudinal direction of the
lapping fixture 50, the matching portions 57a and 57b each have two
parallel planes with a distance formed therebetween larger slightly
than the diameter of the guiding pins 33a and 33b.
[0045] In addition, the matching portions 57a and 57b each have a
curve surface which is opposite to the opening thereof and which
forms part of the matching portion. The distance between the two
curve surfaces is larger slightly than that formed between the
outer sides of the guiding pins 33a and 33b. Therefore, the guiding
pins 33a and 33b inserted in the matching portions 57a and 57b
respectively each have a certain clearance in both vertical and
horizontal direction. The deformation of the lapping fixture 50 is
avoided by the clearance such formed when the lapping fixture 50 is
mounted to the lapping device 1. In other word, in case where no
clearance is present, when misalignment happens between the guiding
pins 33a, 33b and the matching portions 57a and 57b, the lapping
fixture 50 will be mounted to the lapping device 1 in a deformation
state. Consequently, if the row bar 70 is lapped in the deformation
state, the flatness of the ABS will be worsened. On the contrary,
by arrangement of the clearance in each of the matching portions
57a and 57b, the lapping fixture 50 is allowed to have limited
rotation around the attaching hole 56 and horizontal movement in
the attaching hole 56, yet no strong deformation is generated when
mounting the lapping fixture 50 to the lapping device 1.
[0046] Furthermore, the vertical movement of the guiding pins 33a
and 33b can be transferred to the lapping fixture 50 by the
matching portions 57a and 57b independently, such that the lapping
fixture 50 may be pressed downwards and forcefully. In addition,
the cross section of the matching portions 57a and 57b is not
limited to rectangle with rounded corners, any other shape enable
the rotation about the attaching hole 56 and horizontal movement in
the attaching hole 56, such as semicircle may be taken. In
addition, each matching portions 57a and 57b may putting it's
opening facing outside, and in this case, the distance formed
between the two curve surfaces of the matching portions 57a and 57b
is smaller than that formed between the outer sides of the guiding
pins 33a and 33b.
[0047] The holding portion 52 takes the form of a thin and long
beam and can be bent when pressed by an external force. The holding
portion 52 has a width and extends along longitudinal direction of
the lapping fixture 50 such that the holding portion 52 has a
length corresponding to that of the lapping fixture 50. A row bar
securing portion 58 with a plurality of grooves formed therein is
disposed on the bottom side of the holding portion 52 for attaching
a plurality of blades to the grooves, the blades being used for
cutting the row bar.
[0048] Each of the connection members 53a and 53b has an end
coupled to the main body 51, while the other end thereof is coupled
to the holding portion 52, thus forming a flat flexure structure.
Accordingly, deformation of the connection members 53a and 53b is
easy to happen with the bending of the holding portion 52. It is
difficult to prevent deformation of the holding portion 52 from
happening when flexible load is applied thereto. Namely, due to
thin and long structure of the connection members 53a and 53b, the
holding portion 52 may have free rotation along .theta. direction
and movement along horizontal direction to a limited extent at
regions adjacent the connection members 53a and 53b, such that
accidental bending of the holding portion 52 at regions adjacent
the connection members 53a and 53b is avoided.
[0049] Each load-applied portions 54a-54g have a rectangle hole
with rounded corners formed therein for receiving by a certain
clearance the head portions 39a-39g of the load applying pins
36a-36g therein respectively. The load-applied portions 54a-54g are
capable of transferring loads in y direction originated from the
head portions 39a-39g. Each head portions 39a-39g may have any
other suitable sectional shape such as rectangle, ellipse, circle
or crisscross, as long as it can transfer the load in y direction.
The load-applied portions 54a and 54g are disposed at both sides
along longitudinal direction of the row bar securing portion 58
respectively and higher than the rest five load-applied portions
54b-4f, which on the contrary are disposed evenly at middle region
formed between the load-applied portions 54a and 54g. It is noted
that all the load-applied portions may have a same height.
[0050] The central lines of the load-applied portions 54a and 54g
locate outside with respect to the central lines of the two wrist
portions 55a and 55b respectively, while the central lines of the
load-applied portions 54b-54f are consistent with those of the
wrist portions 55b-55f in x direction, respectively. The outward
locations of the central lines of the load-applied portions 54a and
54g can compensate for flexure generated at both sides of the
holding portion 52. Specifically, the loads in y direction applied
to the load-applied portions 54a and 54b are transformed to load
moments in .theta. direction, the load moments being able to
strengthen the flexure generated at sides of the holding portion
52. However, in the embodiment, there are seven load-applied
portions which can sufficiently and accurately control the
deformation of the holding portion 52, as a result, this extending
structure of the load-applied portions 54a and 54g may be omitted
herefrom.
[0051] Then, a method of mounting the lapping fixture 50 to the
lapping device 1 is illustrated. In the following description, take
the load adjusting portion 24d as an example. Firstly, as
illustrated in FIG. 5, the row bar 70 is mounted to the row bar
securing portion 58 by method such as bonding, making the ABS of
the row bar 70 as a bottom surface with respect to the row bar
securing portion 58. The lapping fixture 50 is disposed at front
end of the load applying blocks 35a-35g. The guiding pins 33a and
33b are engaged with the matching portions 57a and 57b of the
lapping fixture 50 respectively, and the head portion 39d of the
load applying pin 36d is received by the hole of the load-applied
portion 54d (same to the other head portions). Additionally, the
fixture securing pin 32 passes through the hole 38 which is larger
enough than the outer diameter of the pin 32, then through the
attaching hole 56, so as to adjust it's position relative to the
lapping fixture 50. In this case, the screw bolt 40 (see FIG. 4) is
inserted from the front end of the lapping fixture 50 to the
attaching hole 56 with a washer 49 disposed between the screw bolt
40 and the attaching hole 56, such that the screw bolt 40 is
screwed with the inner screw of the fixture securing pin 32.
Consequently, the lapping fixture 50 is isolated by the washer 49
and sandwiched between contact surface of the screw bolt 40 and
front end surface of the fixture securing pin 32. Thus, the lapping
fixture 50 is secured by the fixture securing pin 32 which is
connected to the holding portion body 31.
[0052] Next, a method of lapping the row bar 70 using the lapping
device 1 and lapping fixture 50 is described. Here, also take the
load adjusting portion 24d as an example. First, the lapping
fixture 50, which is used for securing the row bar 70, is mounted
onto the lapping device 1 by method illustrated above, then the
carrying base 22 is moved downwards, making the surface to be
processed of the row bar 70 contact with the lapping surface 11a of
the revolving lapping table 11 as shown in FIG. 1. Therefore, the
connection members 53a and 53b are pressed and bear an upward force
applied by the holding portion 52, and a downward force applied by
the main body 51.
[0053] In other words, the holding portion 52 maintains a tight
contact with the lapping surface 11a at position of the connection
members 53a and 53b, that is a first position, and the row bar 70
has its surface to be lapped touched with the lapping surface 11a
(step 1).
[0054] Under this condition, the revolving lapping table 11 starts
to rotate and grind the surface to be lapped of the row bar 70
(step 2).
[0055] As shown in FIG. 5, if the holding portion body 31 is driven
downwards (y direction), the guiding pins 33a and 33b in
conjunction with the matching 57a, 57b and connection members 53a,
53b will push the holding portion 52 downward, thus the lapping
fixture 50 may be provided with a load in y direction (step 3-1).
Moreover, slant manufacturing of the row bar 70 may be adjusted by
adjusting the force applied to the sides of the holding portion
body 31.
[0056] In addition, if move the load transfer rod 25d up and down
(y direction), then the load applying block 35d will move up and
down, also the load applying pin 36d inserted through the load
transfer rod 25 and the head portion 39d will move up and down (y
direction). Accordingly, the MR element height (lapping clearance,
i.e., load clearance) adjacent the load transfer rod 25d is
adjusted by the load transfer rod 25d (step 3-2). In this case, the
load of the guiding pins 33a, 33b in y direction and the load of
the load transfer rod 25d in y direction are controlled
independently from each other.
[0057] These operations mean in other word, providing the surface
to be lapped with load in y direction at a plurality of second
positions on the holding portion 52 and lapping the surface to be
lapped of the row bar 70, the second positions being different from
the first position and disposed longitudinally with intervals
formed therebetween.
[0058] By applying load to the load-applied portion 54d of the
lapping fixture 50, the holding portion 52, row bar securing
portion 58 and row bar 70 will deform properly. Furthermore, as the
load adjusting portions 24a-24g can control the load independently,
it is possible to control the MR element heights and throat heights
of the sliders disposed in the row bar 70 to be their design
values, and at the same time grind the ABS of the row bar 70
evenly.
[0059] Therefore, for the lapping device of the embodiment, as the
load adjusting portions have freedom of load control in y
direction, even if distributions of the MR element height and
throat height of each slider of the row bar 70 are formed
approximately as complex curve of high order, the deformation of
the holding portion 52 may still follow the curve exactly.
Accordingly, the MR element height and throat height of each slider
may be accurately confined to a predetermined range in whole length
of the row bar 70.
[0060] Furthermore, compared with conventional technology, the
method of controlling the MR element height and throat height is
changed slightly. The method is performed by monitoring the
electrical lapping guide (ELG) and resistance of the MR element
such as that disclosed in JP patent gazette NO. 2000-11315 and
patent reference 3. For example, the electrical lapping guide may
be formed in a predetermined position on the wafer and disposed at
both sides along longitudinal direction of the row bar 70. The
lapping device 1 switches between the electrical lapping guide
arrayed on the row bar 70 and resistance of the MR element by a
multiplexer, and monitors them in sequence, then controls the
transfer devices which drive the load adjusting portions 24a-24g.
Firstly the lapping device 1 monitors the resistance of the
electrical lapping guide and performs a rough machining based on
the resistance attained by monitoring, then controls the MR element
height and throat height of each slider such that all the heights
fall within a predefined tolerance range by monitoring resistances
of each MR element.
[0061] The following may give a description of the advantage of the
invention. FIG. 7 is a diagram illustrating the flatness of a row
bar using the lapping fixture of the invention. The reading method
is the same as that of FIG. 9. Suppose that the target value of the
lapping height with respect to the predefined datum is 0.08 .mu.m
with a tolerance of .+-.0.01 .mu.m. In addition, table 1 shows
clearance deviation in longitudinal direction of a conventional row
bar. In the table, conventional technology uses a lapping fixture
shown in FIG. 8. Suppose that the lapping time consumed in
conventional technology is equal to that of the invention, and the
deviation of the MR element height is a standard deviation with
respect to the sample quantity of the row bars to be processed (106
or 130 row bars each of which consists of 40 sliders). MRR (MR
resistance) deviation means the resistance deviation of the MR
element (deviation relative to a resistance of 40.OMEGA.).
TABLE-US-00001 TABLE 1 Con- Number of Deviation nection Lapping row
bars of MR Deviation members time being element of (53a, 53d)
(seconds) processed height MRR The No 12.87 106 0.0041 1.36
Embodiment Prior Art Yes 12.13 130 0.0110 2.75
[0062] As illustrated in the figures and the able, compared to the
prior art, the row bar of the embodiment is lapped with a higher
flatness and smaller deviation in its longitudinal direction which
comprises two end portions, since the press force is applied to all
areas of the row bar having two end portions, thus the bending of
the row bar is avoided. The lapping fixture of the embodiment
equals the conventional lapping fixture shown in FIG. 8, supposed
that the connection members 155a and 155d are removed from the
conventional fixture. In the prior art, if the load-applied
portions 154a and 154g are pressed by a load, the end portions of
the holding portion 52 will deform, and this deformation will
result in displacement with respect to the main body 51 to which no
deformation is produced. Consequently, stress which counterbalances
the load applied by the load-applied portions 154a and 154b is
produced on the connection members 155a and 155d of the end
portions, as a result, sufficient force can not be transferred to
the row bar 70 via the load-applied portions 154a and 154b. In
other hand, in the embodiment, the row bar can be provided with
sufficient force via the load-applied portions 154a and 154b, since
the counter force applied by the connection members 155a and 155d
is non-operative. In addition, since there are no connection
members 155a and 155b, the force applied by the load-applied
portions 154a and 154b can be exerted on the end portions of the
row bar directly, therefore the control precision is also
improved.
[0063] Furthermore, it is noted that the connection members may at
least have the following functions: when the combination of the
lapping fixture 50 and row bar 70 is mounted to the lapping device
1, it is easy to make the row bar 70 kept tight contact with the
lapping surface 11a without additional operation. Setting enough
and necessary load-applied mechanisms which are independent from
the connection members, limiting the connection between the main
body 51 and holding portion 52, and the structure of prohibiting
the counter-force coming from the connection members being
transferred, benefit lapping control of the row bar. Based on this
understanding, the connection members of the lapping fixture of the
embodiment are disposed at least at two positions, and a plurality
of load-applied portions are disposed at inner side and two outer
sides of the connection portions.
[0064] Moreover, the row bar of the embodiment can be lapped more
flatly, as a result, compared with prior art, the flatness
deviation of the embodiment is improved. Thus, it will be a great
advantage of the invention in future when the manufacturing
precision of MR element height is demanded to be highly
improved.
[0065] Furthermore, the invention is not limited to above-mentioned
embodiment, for example, the load-applied portions may only have a
freedom in y direction, or freedom in both y direction and x
direction, or a freedom of y direction and .theta. direction. In
addition, each load-applied portion may have different freedom.
[0066] In addition, the object to be lapped of the invention may
include not only compound thin film sliders with induction-type
magnetic transducer element for writing and MR element for reading
incorporated therein, but also includes thin film sliders with
induction-type magnetic transducer element incorporated therein for
both writing and reading. In addition, the invention may be also
used in polishing or grinding process besides lapping process.
[0067] Understandably, the invention is not limited to slider
processing, but can be used for processing other objects.
* * * * *